Answer:
c=-9
Step-by-step explanation:
Hello,
[tex](ax+b)(x-3)=ax(x-3)+b(x-3)=ax^2-3ax+bx-3b\\\\=ax^2+(b-3a)x+(-3b) \\\\\text{And it should be equal to } 4x^2+cx-9[/tex]
We can identify the like terms so:
a = 4
b-3a = c
3b = 9 <=> b = 3
So c = 3 - 3*4 = 3-12 = -9
Hope this helps.
Do not hesitate if you need further explanation.
Thank you
